Ping uses a series of Internet Control Message Protocol (ICMP) Echo messages to determine:
- Whether a remote host is active or inactive.
- The round-trip delay in communicating with the host.
- Packet loss.
The ping command first sends an echo request packet to an address, then waits for a reply. The ping is successful only if:
- the echo request gets to the destination, and
- the destination is able to get an echo reply back to the source within a predetermined time called a timeout.